Even better. It's all relative to how small the objects on the planet are.

Yeah, but we do need to discuss things in measurements, just so we can make sense of it all.

Ok, so earth's circumference is ~40,075 km

If we have each terrain tile be 1 meter, and we have 1024x1024x6 terrain tiles, the circumference of our planet will be ~6.5 km (6.43398 km to be exact)

if each terrain tile is 3m x 3m, and we have 1024x1024x6 terrain tiles, then the circumference is 19.301 km

if each terrain tile is 3m x 3m, and we have 2048x2048x6 terrain tiles, then the circumference is 38.603 km

That may be a feasible planet size.

So what you're saying is... The planet could be the same size as Earth‽

How much data can be present in each terrain tile, and could a larger size be a problem to creatures only a few centimetres long? Also, how much hard disk would this take up? Questions aside, I was not expecting the possibility of planets of a realistic scale, this is incredible.

No, Uteen, notice how Scio used a comma in the first number and points in the latter two. In other words, 40000 km compared to 38 km.

If my maths aren't wrong, using one byte for each tile on the 38km planet would result in 200MB of data. Of course, that can be reduced a lot (probably even halved) by compressing it with something like zlib, but it's still a lot for mere 38km diameter, and we will certainly want more data per tile. Seems like now it's time to ask the Space Engine's developer.

Last time I checked on Outerra (an engine modelling real size Earth), the height data of Earth took 78GB of space, extremely compressed (about 180GB uncompressed), and that's with 78x78m grid captured by satellites - their trick is using fractal transforms to somehow make the terrain feel real even from a small animal's view. We might have to do something similar to that. I think the Space Engine already does use something like that.

No, Uteen, notice how Scio used a comma in the first number and points in the latter two. In other words, 40000 km compared to 38 km.

If my maths aren't wrong, using one byte for each tile on the 38km planet would result in 200MB of data. Of course, that can be reduced a lot (probably even halved) by compressing it with something like zlib, but it's still a lot for mere 38km diameter, and we will certainly want more data per tile. Seems like now it's time to ask the Space Engine's developer.

Last time I checked on Outerra (an engine modelling real size Earth), the height data of Earth took 78GB of space, extremely compressed (about 180GB uncompressed), and that's with 78x78m grid captured by satellites - their trick is using fractal transforms to somehow make the terrain feel real even from a small animal's view. We might have to do something similar to that. I think the Space Engine already does use something like that.

PS: Roadkill, could you please check your PMs?

Guys, I flubbed a radius. Here's the real values.

Spoiler:

If we have each terrain tile be 1 meter, and we have 1024x1024x6 terrain tiles, the circumference of our planet will be ~3.25 km

if each terrain tile is 3m x 3m, and we have 1024x1024x6 terrain tiles, then the circumference is 9.65 km

if each terrain tile is 3m x 3m, and we have 2048x2048x6 terrain tiles, then the circumference is 19.3 km

In other words, every value I previously said for circumference is halved.

Hold on, so what sort of surface area are we talking about for Earth-sized worlds then? I'm a little lost...

If we have each terrain tile be 1 meter, and we have 1024x1024x6 terrain tiles, the circumference of our planet will be ~3.25 km

if each terrain tile is 3m x 3m, and we have 1024x1024x6 terrain tiles, then the circumference is 9.65 km

if each terrain tile is 3m x 3m, and we have 2048x2048x6 terrain tiles, then the circumference is 19.3 km

The only way to keep a planet on a realistic detail level while adding size is adding faces to it, in essence, quadtreeing the cube again. However, quadtreeing only multiplies the size by 2, while it causes complexity to go up by a power of 2

Surface area for this:if each terrain tile is 3m x 3m, and we have 2048x2048x6 terrain tiles, then the circumference is 19.3 km

surface area of this planet would be +/- 118.6 km[siup]2[/sup]

if we subdivided the cube again, the surface area would be about 474.36 km2

What does that mean? Our planet with a 4096x4096x6 grid and 3m terrain tiles as a cube is over twice the size of Brooklyn. It'a around the size of Brooklyn and queens combined. That might not seem like much, but that's more than half the size of New York City. I'd say that's extremely small, but more than big enough to explore.

I used the method described in that forum, and I've come to an estimate on the circumference of a Spore planet: roughly 2.2 km with a surface area of about 1.5 square km. This means, using scio's Brooklyn sized planet, Thrive planets would have a surface area 316.24 times larger than Spore planets, if I did the math right.

I used the method described in that forum, and I've come to an estimate on the circumference of a Spore planet: roughly 2.2 km with a surface area of about 1.5 square km. This means, using scio's Brooklyn sized planet, Thrive planets would have a surface area 316.24 times larger than Spore planets, if I did the math right.

You did the math right. Well done. Our planet though, will be about .000000929 times the size of earth (in surface area)

I have an idea for the number of planets vs. Size of planets dilemma: most of the solar system is made up of gas giant planets, so if we were to have a few of those (decorative, not explorable - probably not even approachable) in the night sky, it would look like we had a more realiztic number of planets per solar system, but we wouldn't have to render or model them.

Out of the solar system's 8+Pluto planets, Mercury, Venus, Earth and Mars are rocky. Saturn, Jupiter, Uranus and Neptune are gaseous. Pluto is too small to bother with exploring.

We could have 2 or 3 (or even one) explorable rocky planets per system. We could have maybe 1 in 10 (Huuuuge estimate and rounded way, way up in order to keep us from generating too many unusuable planets, feel free to do whatever you like to that number,) capable of supporting life.

So, if we had 20 solar systems, we've got to store 20-25 planets (or less: less is good, right?) and 2-3 of those would be playable.

And now back to discussing quadtrees which I am not allowed to decorate for Christmas.

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It might not be necessary to make Gas Giants unexplorable, all we would have to do is basically store a random seed in the Gas Giants data, along with the normal variables such as Distance from star and orbit. That way only minimal data is needed.

Then the Giant would be generated in not too much detail each time the player goes to the planet.

After all, I doubt many players will get too annoyed if the planet is a little bit different from the last time they were there.

Speaking of which, I don't really know much about Gas Giants but could the Gas composition determined by the distance from the star when it was formed.

It might not be necessary to make Gas Giants unexplorable, all we would have to do is basically store a random seed in the Gas Giants data, along with the normal variables such as Distance from star and orbit. That way only minimal data is needed.

Then the Giant would be generated in not too much detail each time the player goes to the planet.

After all, I doubt many players will get too annoyed if the planet is a little bit different from the last time they were there.

Speaking of which, I don't really know much about Gas Giants but could the Gas composition determined by the distance from the star when it was formed.

It could, but gas giants tend to move about after they form, so we needn't simulate it.